Adverse Effects of Whey Protein

Adverse Effects of Whey Protein | The Paleo Diet

Dear Dr. Cordain,

Could you please provide some details on the benefits/detriments of whey protein supplementation? I am a weight trainer/powerlifter and supplement with whey protein, which is currently touted as the best/most health-conscious choice there is. I have read in your newsletter about the inflammatory aspects of dairy products – is whey protein included in this? Is it better or worse than other dairy products?

Many people interested in the Paleo Diet who are also into strength training and fitness would be interested in your thoughts on this. Any pointers re: inflammation and supplementation of protein would be very well received. Thank you, in advance.

Best regards,

Dr. Cordain’s Response:

Dear Karl,

Unfortunately, at this point, most of the research has focused on the beneficial effects of whey. It basically revolves around whey’s high BCAA content, its use as a post-workout recovery drink ingredient, and its capacity – due to cysteine – to increase Glutathione, a powerful endogenous antioxidant enzyme.

Nevertheless, we believe that whey protein can have some potential adverse effects, because it greatly elevates insulinemia – although it can be therapeutic for diabetics in the short term. We suspect that whey protein could be detrimental long term, as hyperinsulinemia can down-regulate the insulin receptor and lead to insulin resistance. Insulin resistance underlies the Metabolic Syndrome, and is implicated in various other diseases, such as Acne, Alzheimer, various cancers, Coronary Heart Disease, Myopia, PCOS, etc.).

But to be completely sure, we would need intervention studies with whey protein with a relatively long duration in people genetically prone to insulin resistance, or who are in fact insulin resistant.

Also, there is the matter of hormones in milk: estrogens, DHT precursors, Insulin, IGF-1 and the hormone Betacellulin (BTC), which Dr. Cordain has discussed in a previous edition of this newsletter. These are some of the possible mechanisms for which there is repeated epidemiological evidence associating milk consumption with some cancers – especially Prostate Cancer.

We know that these hormones are present in milk and – in the case of BTC – it is present in whey too. Nevertheless, the real content of all these hormones in commercial milk-derived products is an open question that deserves proper and urgent study. So while we don’t know for sure, and since and we have alternatives, I would follow the old saying: do no harm!

Finally, if you have an auto-immune disease or allergy to Beta Lacto Globulin (protein that exists in bovine milk, but nonexistent in human milk) I would stay away from whey. Whey contains not only Beta Lacto Globulin, but also Bovine Serum Albumin. Some peptides from this protein have structural homology with peptides from our own tissues, and BSA has been implicated in Multiple Sclerosis, Rheumatoid Arthritis and Type 1 Diabetes.

In conclusion, I would follow the evolutionary template until all these issues are resolved. which states that recently introduced foods may have potential adverse effects to humans, especially long term. Non-human milk was only introduced in the human diet ~10,000 years ago. Therefore, given the potential health hazards of milk that science is revealing, I would use another protein source. Lean meat and seafood are very good sources of BCAA. If you want a protein drink immediately after strength training to speed recovery and increase muscle mass, I would suggest ~9 grams of essential amino acids, along with a banana.

I hope this helps.

Pedro Bastos

Editor’s note: the following blog posts also discuss whey protein:

Q: I started the program and I was wondering if Whey Protein or protein powder in general is against the diet?

Q: I like drinking protein shakes in the morning, but I noticed some of the protein sources in my protein shake are made from milk or dairy products. Is there an alternative that is available in the market place?

Q: I am just trying to figure out your feelings and thoughts on protein powders.

Additional reading: Hyperinsulinemic diseases: more than just Syndrome X.



About Loren Cordain, PhD, Professor Emeritus

Loren Cordain, PhD, Professor EmeritusDr. Loren Cordain is Professor Emeritus of the Department of Health and Exercise Science at Colorado State University in Fort Collins, Colorado. His research emphasis over the past 20 years has focused upon the evolutionary and anthropological basis for diet, health and well being in modern humans. Dr. Cordain’s scientific publications have examined the nutritional characteristics of worldwide hunter-gatherer diets as well as the nutrient composition of wild plant and animal foods consumed by foraging humans. He is the world’s leading expert on Paleolithic diets and has lectured extensively on the Paleolithic nutrition worldwide. Dr. Cordain is the author of six popular bestselling books including The Real Paleo Diet Cookbook, The Paleo Diet, The Paleo Answer, and The Paleo Diet Cookbook, summarizing his research findings.

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“6” Comments

  1. Hello Dr. Cordain, Your discussion on Whey protein supplementation was very informative and provides a ton of information on the advantages and the negatives of this protein drink. As I am a diabetic , I am very grateful that you discussed this specifically for those prone to insulin resistance too. Please keep posting such useful blogs as it’s really good to have a good knowledge of what we take as supplements.

  2. Whey protein can also be harmful, I never ever thought. Thank you so much for sharing this info….so, if whey is taken without doing the exercise will also harm??? Or do only have to consider the quantity???

  3. I am a bodybuilder following the Paleo Diet as a lifestyle. In addition to strength and endurance training, and beauty sleep, this diet keeps me healthy and lean all year long. I am prepping for my first competition, and rather than lose fat, I need to add muscle. It is my preference to add mass in a healthy, paleo approved way, as I plan to body build for life and am interested in the long term effects of dietary supplements.

    I have been looking at protein powders and discovered this one:

    I am looking for feedback from Dr. Cordain.

    Thank You,

    • Jennifer, my colleague and trusted friend, Pedro Bastos is perhaps the most knowledgeable person in the world to answer this question. His response when I sent him your question was this:

      “Whey protein has a high insulinemic index and it may contain some hormones and growth factors present in milk so for patients who have cancer or a high cancer risk I would stay away from whey. Having said that, in lean highly active individuals the high insulinemic index of whey doesn’t really bother me. Moreover whey has a high amount of leucine and the amino acid absorption rate per hour from whey protein is higher than meat, fish, egg and even egg protein. So if an athlete takes it after exercise it may lead to a higher protein synthesis, since a combined increase in insulinemia and aminoacidemia will signal protein synthesis through the mTOR pathway. Another possible advantage is its high amount of cysteine and more important gamma-glutamyl-cystine which increases the important tripeptide glutathione.

      But do not forget that whey contains some proteins that can trigger an allergic reaction or that people can be sensitive to, such as beta-lactoglobulin and bovine serum albumin. Furthermore in people with some autoimmune diseases bovine serum albumin can be one of the triggers.

      To be on the safe side I suggest: liquid aminoacid formula right after exercise instead of whey protein or egg protein.

      Best wishes.


      Hope this helps,

      Dr. Loren Cordain

  4. I am a bodybuilder following the Paleo Diet. In research on paleo approved protein powders, I read in this article that BSA, Bovine Serum Albumin, has been implicated in MS, RA, and Type 1 Diabetes. On the recommended ‘Food’ link on this site, there is an advertisement for Julian Bakery Paleo Protein Pure (Beef Protein) that touts “Based on bovine serum albumin concentrate—an entirely new protein source only recently made available on a commercial scale.” I find this to be conflicting information and would like more information on BSA.

    Also, near the end of this article, the writer writes, “If you want a protein drink immediately after strength training to speed recovery and increase muscle mass, I would suggest ~9 grams of essential amino acids, along with a banana.” What exactly qualifies as 9 grams of essential amino acids? And what about protein?

    Thank You!

  5. As a highly competitive athlete, training with ultra high intensity I am very intrigued and adhere to Paleo principles. However, I find it difficult to fulfill my protein and nutrient needs solely through whole foods which literally require me to eat 8 – 10 chicken breasts per day if I am to curb my hunger. What is the optimal protein source to integrate into my diet? The Vega protein is great but too pricey and uneconomical. A good natural new zealand whey is certainly more reasonably priced. In addition to BCAA, glutamine and arginine and occasional creatine cycling, is it advisable for me to be consuming a whey protein. I wish to keep my body as clean, alkaline and invigorated as possible for peak physical and cognitive performance.

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